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elaird / supy

analyze events stored in TTrees in parallel
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Python 2.7 #166

Open betchart opened 11 years ago

betchart commented 11 years ago

Hi Ted, Davide, Yossof,

CMSSW > 6 has switched to python 2.7 and ROOT 5.34. We have made a conscious choice in the past to use 2.6 compatible coding in supy, in some cases bending over backwards ( unittest skip and expectedFailure, for example; maybe hackMap, set notation, generator notation). I think a large part of that choice was due to the ease with which we could get a consistent PyROOT environment from CMSSW. Now that CMSSW is moving on, I wanted to see your thoughts on moving to 2.7 environment in our supy/site configurations and coding style expectations. There may be some speed gains to be had, but the reasons why I hope so are a little foggy.

Davide in particular, please comment, since you have a different setup.

Burt

gerbaudo commented 11 years ago

Hi Burt,

I for most of my projects, I am running with both python 2.6 (which is the current version used within the ATLAS setup) and 2.7 (on my laptop). Is there any feature in particular you had in mind that is not going the be available in python 2.7, or you are mostly thinking about improving the code with constructs that were not available in python 2.6 ? I will investigate ATLAS's plan about switching to python 2.7 and I will get back to you as soon as I have more information on this.

Thanks, Davide

betchart commented 11 years ago

Hi Davide,

I think it will be easier to maintain 2.6 compatibility in my coding if I use 2.6, so it makes sense to avoid upgrading if 2.6 compatibility is still a goal. However, the constraint on the CMSSW side is relaxing or relaxed, and everything else being equal, the desire for latest and greatest and carefree coding would be the impetus to abandon 2.6 compatibility. Do check about the ATLAS python plan. We can stick with 2.6 until they also upgrade.

Could be that Ted also has other reasons for desiring 2.6 compatibility.

Burt

gerbaudo commented 11 years ago

Hi Burt,

I just got a reply from one of the ATLAS mailing list. They say that the first ATLAS release built on 2.7 will be deployed in one month. My understanding is that ATLAS and CMS are bound to be ~in sync because they use ~the same set of packages provided by LCG.

Thanks, Davide

elaird commented 11 years ago

Hello,

Both (a) using a 2.7 environment by default; (b) breaking compatibility with 2.6; are fine with me. If the additional work to keep compatibility with 2.6 is small, then I would be in favor of doing so.

Ted